Overview
EN ISO 5456-2:1999 (ISO 5456-2:1996) defines how to produce orthographic representations in technical drawings. It is part of the ISO 5456 series on projection methods and establishes basic rules for arranging and identifying parallel orthogonal projections (flat 2D views) so that objects are represented unambiguously across engineering, architectural and construction documentation.
Key topics and requirements
- Projection methods: Describes the two principal orthographic projection conventions - first angle projection and third angle projection - and shows how each arranges the standard views relative to the principal (front) view.
- Designation of views: Defines the six view directions (A to F) and how to label views and indicate directions of observation using upper- and lower-case letters.
- Reference arrows layout: Permits flexible placement of views using reference arrows when strict first- or third-angle layout is impractical.
- Mirrored orthographic representation: Covers mirrored (face-up) reproductions of objects - a method noted as especially useful in construction drawings.
- Graphical symbols: Annex A (normative) specifies proportions, dimensions and line widths for the identifying graphical symbols used to indicate projection method and mirrored views; it also references ISO 3461-2 for harmonization with other drawing inscriptions.
- General principles: Emphasizes selecting the most informative principal view, minimizing redundant views, and choosing sufficient views, cuts or sections to fully describe an object without ambiguity.
Practical applications
- Producing standardized 2D engineering drawings and manufacturing documentation that are internationally interpretable.
- Setting CAD drawing templates and title-block symbols to indicate projection convention (first vs third angle).
- Creating construction and architectural drawings where mirrored orthographic representation may simplify presentation.
- Training and quality-control for drafting, technical illustration and documentation to ensure consistent view arrangement and labeling.
Who should use this standard
- Mechanical, electrical and civil engineers
- CAD technicians and draftspeople
- Technical illustrators and document authors
- Quality and compliance teams in manufacturing and construction
- Standards writers and educators teaching drawing conventions
Related standards
Keywords: EN ISO 5456-2, ISO 5456-2, orthographic representation, first angle projection, third angle projection, projection methods, technical drawings, graphical symbols, reference arrows.
